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Linnaeus put organisms into groups based on physical characteristics.
The Linnaean system of classification has 7 levels:
KINGDOMPHYLUMCLASSORDERFAMILY GENUSSPECIES
Levels get increasingly specific from kingdom to species.
• The “Tree of life” summarizes the evolutionary history of all life on Earth in one simple graphic organizer• A wide variety of living organisms have inhabited Earth over millions of
years
• Many species went extinct at different points in Earth’s history
• 97% of all things have died out
• Rate is not uniform
• Modern living organisms would be “green leaves” on the tree
Kingdom--------
Phylum---------
Subphylum------
Class-----------
Order-----------
Family----------
Genus----------
Species---------
Animalia
Chordata
Vertebrata
Mammalia
Primates
Hominidae
Homo
sapiens
Scientific Name for humans = Homo sapiens or Homo sapiens
• 2 word system of naming• Written in Latin because it’s not used
• Common names may differ in different regions• Example: puma, mountain lion, cougar: all the same animal
• Common names may be misleading• Example: Worms
• Ringworm is a fungus
• Meal worm is an insect larvae
• Scientific names allow for precision
Organisms adapted to their environments
through acquired traits
change in their life time Use & Disuse
organisms lost parts because they did not use them — like the missing eyes & digestive system of the tapeworm
Perfection with Use & Needthe constant use of an organ leads that organ to increase in size — like the muscles of a blacksmith or the large ears of a night-flying bat
transmit acquired characteristics to next generation
1809-1882
British naturalist
Proposed the idea of evolution by natural selection
Collected clear evidence to support his ideas
Warbler finch
Woodpecker finch
Small insectivoroustree finch
Largeinsectivorous
tree finch
Vegetariantree finch
Cactus finch
Sharp-beaked finch
Small groundfinch
Mediumground finch
Large groundfinch
Insect eaters
Bud eater
Seed eaters
Cactuseater
Studied and took samples of different birds◦ Found 14 different species of finch—but only 1 was
located on the mainland.
Differences in beaks
associated with eating different foods
adaptations to foods available on islands
Seedeaters
Flowereaters
Insecteaters
Finches with beak differences that allowed them to…
◦ successfully compete
◦ successfully feed
◦ successfully reproduce
pass successful traits onto their offspring
1. All individuals in a population have variations.
2. Some of these variations allow individuals to successfully compete.
3. Those that “win” at competition are able to eat to survive.
4. The individual is able to reproduce and pass their variations on to their offspring.
Darwin called this:
Voyage: 1831-1836November 24, 1859, Darwin published
“On the Origin of Species by Means of Natural Selection”
A variation is considered an Adaptation when the trait enhances an organism’s ability to survive in a particular environment.
•Increases the fitness to the environment
•Increases the chance for reproduction/ survival and passing on its genes•Product of evolution by natural selection
•Example: size of moose’s antlers, coloring of a mouse
As more organisms survive with this variation, it will become more common in the gene pool.
This can lead to the development of new species!
A species can be defined as: a group of organisms that are able to interbreed and produce fertile offspring.
1. Behavioral- involves response to an organism’s environment
• Examples: birds migrate, bears hibernate, salmon swimming to spawning ground
**Remember, if it increases the survival of the organisms, then they can pass that trait on!!
• 2. Physiological: involves the function of a trait
• Example: poison of snakes,
• ink of octopus, etc.
3. Structural: involves the anatomy of an organism
• Example: bird’s beak
• horse's hoof
• anteater snout, ect.
• A method of hiding from predators by making oneself appear part of the natural surroundings
• When an organism imitates another organism for survival• Smaller, weaker animals have to imitate stronger
animals to stay alive.
• Insects or other less powerful animals can trick their predators into thinking they are a different animal by:• the sounds they make
• the colors on their body
•Examples:•Viceroy butterfly is a mimic of the monarch because the monarch is bitter to eat•Caterpillar mimics the look of a snake•Fly that mimics the look of a bee•Scarlet king snake mimics the coral snake (venomous)
Insecticide & drug resistance◦ insecticide didn’t
kill all individuals
◦ resistant survivors
reproduce
◦ resistance is inherited
◦ insecticide becomes
less & less effective
Other EXAMPLES?
LaMarck◦ in reaching higher
vegetation giraffes stretch their necks & transmits the acquired longer neck to offspring
Darwin◦ longer-necked giraffes survive
better & leave more offspring who inherit their long necks
VARIATIONS IN THE GENES!!
Are the living organisms we observe today the same as they were millions of years ago?
• Many species appear to have changed to various degrees over time giving rise to the modern forms of life we observe today
• All living organisms trace their history back
to various common ancestor “branches”
which ultimately traces back to a single common ancestor “tree trunk”
• humans and chimpanzees shared a common primate ancestor in the past ???
Fossil record◦ transition species
Anatomical record◦ homologous & vestigial structures
◦ embryology & development
Molecular record◦ protein & DNA sequence
Artificial selection◦ human-caused evolution
Layers of sedimentary rock contain fossils
◦ new layers cover older ones, creating a record over time
◦ fossils within layers show that a succession of organisms have populated Earth throughout a long period of time
Life’s Natural History is a record of Successions & Extinctions
Quaternary
Tertiary
Cretaceous
Jurassic
Triassic
Permian
Carboniferous
Devonian
Silurian
Ordovician
Cambrian
Ediacaran
Precambrian,
Proterozoic,
&
Archarozoic
An
aero
bic
Bacte
ria
Insects
Rep
tile
s
Din
osaurs
Mam
mals
Bir
ds
Land P
lants
Seed P
lants
Pla
nts
Art
hro
pods
Ch
ord
ate
s
Jaw
less F
ish
Tele
ost
Fis
h
Am
phib
ians
Photo
synth
eti
c B
acte
ria
Gre
en A
lgae
Mult
icellula
r A
nim
als
Molluscs
1.5
4500
700
63
135
180
225
280
350
400
430
500
570
Flo
weri
ng
mya
Millions of years ago
50
100
150
200
250
300
350
400
450
500
550
60 55 50 45 40 35 30 25 20 15 10 5 0
Equus
HyracotheriumMesohippus
Merychippus
Nannippus
Body s
ize (kg)
Some species have evolved to be larger over time.
How does that work?
The horses that were born slightly larger were better able to escape predators andpass their “large bodysize” traits to their offspring.
Archaeopteryx◦ lived about 150 mya
◦ links reptiles & birds
• Links sea animals and land animals
New layers of rock cover older layers of rock
Scientists find fossils that exist in different layers
The fossils are linedup according to TIME
Similarities andDifferences are noted betweenfossils
*Ancestry is establishedor not established
1. Homologous Structures = similar shape, but different modern function◦ Similar forelimb bone structures for human, cats,
whales, & bats suggest they shared a common ancestor a long time ago
Modern animals may have structures that serve little or no function that were functional in ancestral species
◦ evidence of change over time
some snakes & whales show remains of the pelvis & leg bones of walking ancestors
eyes on blind cave fish
human tail bone
Why would whales have leg bones if they were always sea creatures?
Similar embryological development in closely related species◦ all vertebrate embryos have similar structures at
different stages of development
All of these creatures have gill pouches as embryos
This suggests a common ancestor that lived in the sea
3. Comparative Embryology
Comparing molecules of DNA and Proteins (sequences
of Amino Acids) can help biologists understand how closely related different species are.
◦ universal genetic code! DNA & RNA
◦ compare common genes
Closely related species have sequences that are more similar than distantly related species DNA & proteins are a molecular
record of evolutionary relationships
Number of amino acid differences betweenhemoglobin (146 aa) of vertebrate species and that of humans
100 20 30 40 50 6070 80 90100110120
LampreyFrogBirdDogMacaqueHuman
328 45 67 125
Figure 15.12A
Pleistocene
Pliocene
Mio
ce
ne
Oli
go
ce
ne
Brown bearPolarbear
Asiaticblack bear
Americanblack bear
Sunbear
Slothbear
Spectacledbear
Giant
pandaRaccoon
Lesser
panda
Ursidae
Procyonidae
Common ancestralcarnivorans
A Phylogenetic Tree recently revised based on comparative biochemistry suggests that the Giant Panda is more closely related to bears than raccoons
Artificial breeding can use variations in populations to create vastly different “breeds” & “varieties”
Lots of hidden variations come out!